U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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Efficacy and Safety Studies for Cancer Immunotherapeutics

 

1. Purpose and Background 

This memorandum provides guidance on conducting safety and efficacy studies for 

cancer immunotherapeutics. This Veterinary Services Memorandum (VSM) supplements

existing Center for Veterinary Biologics (CVB) guidelines: including VSM 800.200, General 

Licensing Considerations: Study Practices and Documentation, VSM 800.202, General 

Licensing Considerations: Efficacy Studies for Prophylactic and Therapeutic Biologics;

VSM 800.301, Good Clinical Practice; VSM 800.207, General Licensing Considerations: 

Target Animal Safety (TAS) Studies Prior to Product Licensure - VICH Guideline 44; and 

VSM 800.121, Autologous Therapeutic Biologics.

Cancer immunotherapies are used in the treatment of animals diagnosed with cancer, as 

opposed to conventional vaccines, which are administered to healthy animals to prevent 

infectious disease. This difference and the heterogeneity of naturally occurring neoplastic 

disease requires unique safety and efficacy studies when evaluating immunomodulatory 

cancer products, unlike safety and efficacy studies used in evaluating biologics used for 

infectious agents. CVB’s intention is to address these fundamental differences by 

establishing requirements for demonstrating safety and efficacy for these products. The 

design of these studies, the acceptable level of risk of adverse events, and the standard 

for efficacy must balance the benefits versus the risks to the patients. This risk is 

compounded by the necessity of using client-owned animals, with naturally occurring 

disease, to determine efficacy during early product development. The guidance in this 

memo applies to the evaluation of biologics that are cancer immunotherapeutics used to 

treat neoplastic disease, including autologous immunotherapeutics. CVB expects that 

aspects of the guidance will also apply to immunomodulatory products for nonneoplastic disease that involve client-owned animal studies in product development.

Pursuant to the Congressional Review Act (5 U.S.C. § 801 et seq.), the Office of 

Information and Regulatory Affairs designated this rule as a non-major rule, as defined by 

5 U.S.C. § 804(2). 

2. Document Status 

A. Issue Date: 09/02/2020. 

B. This is a new document. 

3. Authority and References 

A. Authorities 
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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7 CFR 371.4

9 CFR 101.2

9 CFR 102.6

9 CFR 103.3

9 CFR 116.9

 

B. References 

1) VICH Guideline (GL) 43 (Target Animal Safety for Veterinary Pharmaceutical 

Products)

2) VSM 800.121, Autologous Therapeutic Biologics

3) VSM 800.200, General Licensing Considerations: Study Practices and 

Documentation

4) VSM 800.202, General Licensing Considerations: Efficacy Studies for Prophylactic 

and Therapeutic Biologics

5) VSM 800.204, General Licensing Considerations: Field Safety Studies

6) VSM 800.205, General Licensing Considerations: Biotechnology-derived Veterinary 

Biologics Categories I, II, and III

7) VSM 800.207, General Licensing Considerations: Target Animal Safety (TAS) 

Studies Prior to Product Licensure

8) VSM 800.301, Good Clinical Practice 

4. Audience 

VS employees and members of the biologics industry. 

5. Guidance 

The applicant must design strategically focused studies that demonstrate efficacy and 

safety within a specific species against a single tumor type or specific biomarker. For all 

cancer products, CVB will usually require an investigator to first conduct preliminary 

studies and then pursue conditional licensure prior to proceeding to full licensure.

A. Preliminary Studies Required Prior to Performing Pivotal Combined Safety and 

Efficacy Studies 

The applicant must demonstrate that the product is supported by scientifically sound 

theory and that the risks of using the product outside the laboratory in client-owned 

animals are addressed prior to performing pivotal safety and efficacy studies in clientowned animals for conditional licensure. Data necessary to address these 

requirements can be obtained through small pilot studies, related previously 

conducted studies, and peer-reviewed publications involving research animals and 

client-owned animals. CVB acceptance of these small-scale, preliminary studies is 
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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needed before pivotal studies would be allowed in client-owned animals, but does 

not imply that the normal licensure requirements for these issues are met.

1) Supportive Studies

The applicant should submit any studies, including the supporting data, 

completed prior to the pre-licensing process or performed in other species that 

model the mode of action, for consideration as supportive evidence in the

evaluation of safety, efficacy, mechanism of action, and environmental risk 

assessments. CVB values comparative oncology research because of its potential 

to advance both veterinary and human immunotherapies. Applicable studies 

used in the development of human products that have been previously reviewed 

and approved by other Federal agencies have the potential to meet CVB

requirements.

2) Environmental Release and User Safety Studies

Prior to performing any studies outside the laboratory, the applicant should 

address risks to the environment or to user safety caused by inadvertent human 

exposure to the product. The applicant will evaluate the risks and any necessary 

control measures needed to limit human exposure to the product during the 

product administration or care of the animal after treatment. The procedure for 

evaluating these potential risks is in VSM 800.205, General Licensing 

Considerations: Biotechnology-derived Veterinary Biologics Categories I, II, and

III.

3) Demonstration of Proof of Concept in Target Species

Prior to performing pivotal combined safety and efficacy studies, CVB expects 

the applicant to have demonstrated a defined mechanism of action or have 

demonstrated an immune response likely to provide an anti-neoplastic effect 

with the product. This product-specific data should be supported by scientifically

sound theory. These studies exploring the mechanisms of action are necessary 

for the applicant to properly design future combined safety and efficacy studies. 

Either in vitro studies or in vivo pilot studies can be used to demonstrate the 

mechanism of action in the target species. Product-specific, in vivo studies may 

be done either prior to, or as part of, conditional licensure efficacy studies in 

client-owned animals with adequate justification. For example, if the applicant 

has a product with a mechanism of action that targets and depletes a specific 

cell type, then the investigator’s analysis of the study should confirm an immune 

response and/or depletion of that cell type in vivo in the target species. This type 

of study is integral to any scientifically sound product development plan.
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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4) Safety Studies

CVB establishes safety study requirements for each product dependent upon the 

expected adverse events, based on similarly classified immunotherapeutics and 

the optimal methods to identify adverse events. While CVB expects there will be 

minimal adverse reactions with some cancer immunotherapeutics, there may be 

consequential unforeseen adverse reactions with other products. CVB 

encourages firms to submit safety study protocols for review for suitability prior 

to beginning the study and to supply relevant safety study references describing 

existing human or animal products that act by a similar mechanism as the 

proposed product. The applicant should provide previously generated safety 

data, as applicable and specific to the experimental product, to CVB for 

evaluation. Prior to conducting pivotal studies, the applicant should complete an 

initial target animal safety study, followed by acquisition of additional safety data 

later in the licensing process. This is recommended to identify potential adverse 

events prior to using the therapy in large numbers of client-owned animals 

necessary for a pivotal study. 

a. If the applicant can provide safety data from pilot studies in client-owned 

animals that meet the intent of this requirement, the target animal safety 

testing study using research animals may be postponed until later in the 

licensing process. Additionally, some products, such as autologous cancer 

products, may be allowed to use alternative study designs using only clientowned animals if the study design meets the intent of this requirement.

b. For the target animal safety study, the applicant is generally required to 

administer the product at or above the normal dosage following the normal 

treatment schedule to a minimum of eight (8) target species animals. CVB 

generally requires such studies to last a minimum of two (2) months after 

initiating therapy. CVB requires physical examinations and daily observations 

for acute reactions, hematology, serum biochemistry, and urinalysis at 

appropriate intervals. The investigator is not required to include negative 

control animals in the study and is only required to perform postmortem 

examinations of the study animals if adverse events or abnormal laboratory 

test results warrant further investigation. Investigators should follow the 

guidance in VSM 800.207 for general aspects of study design.

c. Describe and report adverse events identified in these safety studies using 

the published Veterinary Cooperative Oncology Group (VCOG) consensus 

document on common terminology for adverse events.1

d. If CVB determines that the initial safety data is satisfactory, then CVB may 

allow the investigator to perform pivotal combined efficacy and safety 
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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studies in client-owned animals with neoplastic disease.

5) Pilot Efficacy Studies

CVB may allow pilot efficacy studies following title 9, Code of Federal Regulations

(9 CFR) part 103.3 on multiple tumor types in multiple species to broadly 

evaluate the product for evidence of efficacy and safety. The goal of these pilot 

studies is to determine all the necessary conditions to design and run an 

informed pivotal safety and efficacy study. The applicant should use pilot studies 

to identify additional safety information and to determine how the product will 

be used, including determining labeling for specific tumor types, species, dose, 

and treatment schedules.

B. Combined Pivotal Field Efficacy and Safety Study Considerations for Conditional 

Licensure 

CVB requires applicants to design a pivotal study to demonstrate a reasonable 

expectation of efficacy and an acceptable safety profile based on the information 

acquired from the preliminary studies described in Section 5.A. The pivotal study data 

will be used to support and obtain an initial, conditional license, generally a required 

step prior to obtaining full licensure for cancer immunotherapeutics. The eligibility to 

obtain a conditional license will follow 9 CFR 102.6, but CVB recognizes that 

neoplastic disease is very heterogeneous, even within a single tumor type, and 

curative biologic therapies are rarely available.

Applicants should use a study design and practices that broadly follow the guidance in 

VSM 800.202, General Licensing Considerations: Efficacy Studies for Prophylactic and 

Therapeutic Biologics; and VSM 800.301, Good Clinical Practice. Some of the 

guidance in those documents is aimed at studies based on exposure to an infectious 

pathogen and the applicant should propose modifications to those features to better 

suit the evaluation of an immunotherapeutic treatment for spontaneously occurring 

disease. CVB recommends submitting a protocol for review well in advance of 

initiating these complex studies. Additionally, the protocol should include a method 

to evaluate patient quality of life into the study design to develop supportive 

information for the product.

The ideal efficacy study evaluates overall survival; however, CVB may allow studies 

using surrogate endpoints. Surrogate endpoints allowed by CVB include 

disease/event-free survival, progression-free survival, time to progression, and 

objective response rates. CVB may also consider other alternative study end points, 

as well as rigorous adaptive trial designs. Studies using multi-agent therapy must also 

follow the guidance within Section 5.D. All studies should follow the “intention to 
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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treat principle” to avoid inappropriately excluding animals enrolled into the study 

from the analysis.

Both longitudinal studies and objective response studies are acceptable methods to 

demonstrate efficacy for conditional licensure. Specific requirements for these two 

(2) common efficacy study designs and the requirements for the concurrent safety 

component of these studies are listed below.

1) General Requirements for Longitudinal Efficacy Studies

a. Longitudinal studies are those tracking time-based endpoints, such as overall 

survival, progression-free survival, and time to progression. CVB requires such 

studies to be prospective, at least double-armed, randomized, and blinded. 

Patient selection and stratification must be done on prognostic indicators 

demonstrated to have a predictive value for both treatment and control 

groups. The applicant must fully describe and justify criteria for inclusion or 

exclusion of patients from the study. Each patient should have a wellcharacterized tumor type diagnosis using appropriate diagnostic methods. 

Include other relevant prognostic factors, such as tumor subtype, tumor 

grading, clinical staging, and previous or concomitant therapies, in the final 

report even if these factors were not used for patient selection or 

stratification. The control group should receive an ethically and clinically 

appropriate therapy or placebo. For example, an acceptable study design 

might compare a treatment group that receives the experimental 

immunotherapy plus the standard of care therapy against a control group that 

only receives the standard care therapy. 

b. For studies with rolling enrollment, CVB recommends randomization within 

sequential blocks of subjects (permuted block randomization). Block size 

should be a multiple (e.g., one time (1x) or two times (2x)) of the number of 

treatment groups. CVB prefers a two times (2x) multiple block size to diminish 

the possibility of spontaneous unblinding, but this may be logistically 

infeasible if enrollment at individual sites is expected to be low. Applicants 

must stratify randomization on major prognostic indicators demonstrated to 

have a predictive value for the specific tumor type and species in the study. 

Each enrollment site should have its own randomization schedule, which can 

be maintained either locally or by a central offsite authority. The use of 

slightly unequal numbers of animals in the treatment and control groups, up 

to a two-to-one (2:1) ratio, would generally be acceptable. 

c. CVB will consider variations on the standard longitudinal study design shown 

above (5.B.1.b) if CVB determines that the proposals are statistically sound 

and there is strong justification for the alternative study design. Because the 
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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study design variations shown below may weaken the study results, the 

applicant should design the study to account for the additional uncertainty 

caused by these variations. Examples of alternatives to the standard study 

design that may be considered are: 

i. Use of data from a non-randomized, concurrent, prospectively selected, 

matched population of animals receiving standard of care therapy by 

board-certified oncologists at a minimum of three (3) specialty hospitals as 

the control group. The control group in this study design would be less 

effective than the use of a randomized and blinded control group. 

ii. CVB discourages use of historical data as a comparator to a treatment 

group. CVB discourages investigators from using this study type because 

there are proven disadvantages to using historical data when examining 

progression-free survival or overall survival. CVB may consider allowing 

this under very limited and specific circumstances for conditional 

licensure, but not for full licensure. CVB may allow use when the historical 

data from multiple sources with similar study designs and study 

populations all demonstrate that disease progression and response to the 

current standard of care is well characterized and consistent.

iii. CVB recognizes that blinding may not be feasible for all therapies and will 

consider alternative study designs in these unique circumstances. 

2) General Requirements for Objective Response Efficacy Studies

Objective response studies are single arm, non-randomized, non-blinded studies 

which objectively measure responses, such as a decrease in tumor size or volume. 

CVB may consider other measurable responses, such as a decrease in circulating 

neoplastic cells, as meaningful objective responses if they are both well 

recognized and highly clinically relevant. CVB requires such studies to enroll 

animals that will be observed for a minimum of four (4) months after treatment, 

so that preliminary temporal data on disease progression or survival are also 

collected. The applicant should follow study design and tumor response 

evaluation guidance described by nationally or internationally recognized 

organizations, such as the VCOG consensus document on response evaluation 

criteria for solid tumors or the Response Evaluation Criteria in Solid Tumours 

(iRECIST) guidelines for immunotherapeutics.2,3 The investigator must blind 

clinicians to previously recorded measurements at the time of each assessment. 

Documenting measurements via digital imaging is generally recommended and 

representative images should be included in the final report as appropriate. 

3) Safety Evaluation and Adverse Event Reporting for Conditional Licensure
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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The applicant must design both longitudinal and objective response rate efficacy 

studies to concurrently evaluate product safety. Design the safety monitoring 

portions of the study to fully identify and evaluate any adverse events (AE). 

Perform observations for both subclinical and clinical adverse events through 

physical examinations, hematology, serum biochemistry, and other appropriate 

methods at regular intervals.

a. The applicant should generally follow the applicable sections of VSM 800.204,

General Licensing Considerations: Field Safety Studies, for identifying AEs in 

companion animals, assessing the relationship of the AE to the product, and 

the AE reporting requirements, unless otherwise noted below.

b. The firm must describe and report adverse events following the VCOG 

consensus document on common terminology for adverse events.1

c. Perform complete postmortem examinations, including histopathology, on 

available patients that die during the trial to evaluate subclinical/clinical AEs 

and to define the level of disease progression at the time of death. At a 

minimum, perform postmortem examinations on patients for which the cause 

of death is unclear or there are significant subclinical or clinical abnormalities 

not clearly attributable to an identified cause before death. Thorough and 

timely antemortem evaluations of patients using diagnostic imaging and other 

examinations to access both the cancer status and overall health of the 

patients may be an acceptable replacement for postmortem examinations in 

appropriate circumstances, such as when an owner does not allow a 

postmortem examination. 

C. Combined Efficacy and Safety Study Design Considerations for Full Licensure 

The applicant should design full licensure studies that will demonstrate product 

efficacy and safety in a larger population of patients than was required for 

conditional licensure. The study should reflect the product’s planned clinical use, so 

that the benefits and risks of the product are fully understood. This larger group of 

patients may expose additional adverse responses, which will require developing 

corrective measures prior to full licensure and widespread use of the product.

1) Efficacy Study Designs for Full Licensure

Efficacy study designs to support full licensure should generally follow the 

guidance for conditional licensure, but their design and analysis must be fully 

pre-specified in explicit detail. The firm should submit a protocol and consider 

CVB’s response before beginning the study. Typically, greater numbers of 

subject animals are expected in studies supporting full licensure than for 

conditional licensure. When appropriate, a well-designed conditional licensure 
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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study could potentially expand enrollment to meet the requirements of full 

licensure, if the study designs in both the conditional and full licensure studies 

are complementary. Submission of a single protocol for both conditional and full 

licensure may be allowed, but it should be recognized that information learned 

during the condition licensure study may require changes to the full licensure 

protocol.

a. CVB allows surrogate endpoints in place of overall survival as the primary 

variable, as described for conditional licensure. However, all studies must 

include a measurement of the duration of the effect by the immunotherapy 

in the treatment group compared to the control group as a primary variable. 

For example, while an objective response study alone may be acceptable for 

conditional licensure, full licensure would require efficacy be evaluated both 

by objective responses and progression-free survival endpoints.

b. CVB expects that overall survival will be a secondary variable for determining

efficacy.

c. CVB allows studies using multi-agent therapy if they follow the guidance 

within Section 5.D.

d. All studies should follow the “intention to treat principle” to avoid 

inappropriately excluding animals enrolled into the study from the analysis. 

CVB may consider additional analysis methods based on a “per protocol” 

selection of patients supported by strong justification.

e. The applicant should include methods to evaluate quality of life for the 

patient in the study design; however, CVB will only consider these results as 

supportive data. Subjective or semi-quantitative evaluations of quality of life 

should use appropriate blinding when possible.

2) Safety Evaluations and Adverse Event Reporting for Full Licensure

The applicant must design efficacy studies for full licensure to concurrently 

evaluate product safety. Monitoring, evaluation, and reporting of AEs associated 

with the product from only animals enrolled in the pivotal study should generally 

follow the guidance for conditional licensure studies. However, safety 

evaluations should be updated to account for any AE findings uncovered during 

the previous conditional license study.

Properly designed combined efficacy and safety studies in client-owned 

animals that well characterize the AEs of the product may negate the need for 

additional pre-licensing safety studies in healthy research animals. This will be 

determined based on the adverse events observed, and how thoroughly the 

patients were monitored for both clinical and subclinical adverse events. If the 
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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AEs from the product are not well characterized during efficacy studies in 

client-owned animals, investigators will be required to perform additional 

safety studies in the target species using healthy research animals. These 

studies in healthy research animals would follow VICH GL43 (Target Animal 

Safety for Veterinary Pharmaceutical Products) or other approved study 

designs.

D. Evaluation of Efficacy and Safety When Used as Part of a Multi-Therapy Treatment 

Regimen 

The applicant must provide CVB with rationales that address the issues listed below: 

1) The study design must demonstrate and distinguish the positive and negative

effects of the experimental biologic from the other concomitant therapies 

through the use of appropriate control groups or other methods.

2) There is strong justification for the use of each concurrent therapy or drug.

3) The concurrent therapies proposed are broadly recognized and widely used in 

the specific clinical setting described in the study.

4) The therapeutic effects and side effects are well understood and documented 

for the concomitant treatment regimen.

5) The treatment protocols’ concurrent surgical, radiological, or chemotherapies 

are well defined and standardized within the study.

6) Use of the concurrent therapies in the target species does not violate

regulations from other Federal agencies.

7) CVB expects product labeling to fully define the multi-therapy treatment regimen 

used in the pivotal studies.

8) No endorsement of efficacy or safety is made of the concurrent therapies 

in labeling. 

E. Licensure Pathway 

In general, CVB requires cancer immunotherapies to be conditionally licensed for a 

period of time prior to progressing to full licensure. CVB re-evaluates conditionally 

licensed products for safety, efficacy, and progression toward full licensure at least 

every two (2) years. If CVB determines that the product continues to have an 

acceptable level of safety and the firm has made progress toward full licensure, then 

CVB reissues the conditional license for an additional two (2) years.

1) The firm is generally expected to meet CVB requirements to obtain a full 
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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license within six (6) years of first achieving conditional licensure. CVB may 

consider extending conditional licensure beyond six (6) years if the firm is 

developing a therapy for a type of cancer with low prevalence and 

demonstrates meaningful progress toward licensure.

2) CVB subjects conditionally and fully licensed products to normal post- licensure 

AE monitoring and reporting under 9 CFR 116.9, or as otherwise required by 

CVB. However, as licensed products are used on a larger population of animals, 

the likely need to refine product label warnings based on AE reporting will be 

more common in cancer immunotherapies than with conventional infectious 

agent vaccines. CVB requires the firm to carefully monitor the product for AEs, 

including lack of efficacy in subpopulations of patients, as defined in 9 CFR 

101.2. Firms must be in close communication with CVB, so that any AE can be 

rapidly addressed as required under 9 CFR 116.9.

3) Reporting and product label warnings of AEs will be categorized based on the 

stage of licensure and the source of the AE. 

a. Report AEs identified during the pivotal conditional licensure study to CVB as 

part of the final combined efficacy and study report. The firm must describe 

and report adverse events following the VCOG consensus document on 

common terminology for adverse events.1 These AEs will be the basis for the 

labeling warnings and the safety Individual Study Summary (ISS) for the 

conditionally licensed product. Only AEs that are reasonably associated with 

the product as determined by CVB will be required to be on product labeling 

and these events will be termed “adverse reactions” on product labeling to 

distinguish them from the more broadly defined term of “adverse events.” 

All AEs will be required to be placed in the ISS. The AEs listed in the ISS can 

be accompanied by an explanation such as: “Adverse Event: Any unfavorable 

and unintended event that occurs after the use of the product, whether the 

cause of the adverse event is known to be attributed to the product or is not 

attributed to the product, such as pre-existing disease.”

b. Spontaneously reported AEs obtained from product use in animals not 

enrolled in pivotal studies should be reported separately from AEs observed 

in pivotal studies. This reporting should follow 9 CFR 116.9 regulations.

Additionally, CVB requires an annual safety report describing all 

spontaneously reported AEs, using the Veterinary Dictionary for Drug 

Related Affairs, or VeDDRA, terminology and assigning causality following the 

ABON system during conditional licensure and for the first two (2) years of 

full licensure. This annual report is in addition to the normal AE reporting 

requirements. If necessary, AEs identified through spontaneous reporting 

may be added to the label warnings. The label text distinguishes these 
U.S. DEPARTMENT OF AGRICULTURE 

Marketing and Regulatory Programs

Animal and Plant Health Inspection Service

Veterinary Services 

VS Memorandum 800.126 

 

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spontaneously reported AEs from those identified in pivotal studies.

c. AEs identified in animals enrolled in the pivotal combined efficacy and safety 

study for full licensure will be addressed as is described for the pivotal 

conditional licensure study AE. 

6. Citations 

1) Veterinary cooperative oncology group - common terminology criteria for adverse 

events (VCOG-CTCAE) following chemotherapy or biological antineoplastic therapy in 

dogs and cats v1.1. Vet Comp Oncol. 2016 Dec; 14(4):417-446.

2) Nguyen SM, Thamm DH, Vail DM, London CA. Response evaluation criteria forsolid 

tumours in dogs (v1.0): a Veterinary Cooperative Oncology Group (VCOG) consensus 

document. Vet Comp Oncol. 2015 Sep; 13(3):176-83.

3) Seymour L, Bogaerts J, Perrone A, Ford R, et al. iRECIST: guidelines for response 

criteria for use in trials testing immunotherapeutics. Lancet Oncol. 2017Mar;

18:e143-e152. 

7. Implementation/Applicability 

Updated policy in this memorandum is effective immediately.